1. Field of the Invention
The present invention relates to image pickup apparatuses such as video cameras, electronic still cameras, and digital still cameras.
2. Description of the Related Art
Conventional image pickup apparatuses such as video cameras, electronic still cameras and digital still cameras employ optical zooming which optically enlarges an image with an optical unit like a zoom lens, and electronic zooming which enlarges an image by electronic processing. The electronic zoom introduces deterioration in the quality of the image. Thus, for the resolution of the image to be maintained, a technique for using the electronic zoom after optically enlarging the image as large as possible is generally used.
FIG. 10 shows a schematic chart illustrating such optical and electronic zoom operations in an image pickup apparatus like a video camera. Its horizontal axis represents the operating time of a zoom switch (not shown), while its vertical axis represents changes in view angle from a wide angle (shown as W) to a telephoto angle (shown as T). Initially, between point a where enlargement of an image begins and point b, only optical zooming is performed to its limit. If further enlargement of the image is needed, electronic zooming is performed from point b to point c so that a desired view angle is obtained.
In optical enlargement of the image, the image can hardly be rapidly enlarged because the zoom lens is mechanically driven. If such rapid enlargement of the image is needed, a technique for simultaneously performing the optical zooming and rapid electronic zooming which uses electric operations is schematically shown in FIG. 11.
However, rapid zooming can hardly be performed in a range where only the optical zooming (which mechanically drives lenses) is performed.
In addition, although the image can rapidly be enlarged by the zoom operation as shown in FIG. 11, the problem of deterioration in resolution, caused by the electronic zoom, still remains.
Accordingly, in view of the foregoing problems, it is an object of the present invention to provide an image pickup apparatus with a rapid zoom function, in which deterioration in the image quality, caused by operation of the zoom function, is minimized.
According to an aspect of the present invention, the foregoing object has been achieved through the provision of an image pickup apparatus including: first adjustment means for optically adjusting a view angle; second adjustment means for electronically adjusting the view angle; commanding means for giving a view-angle change command; first control means for causing the second adjustment means to adjust the view angle based on the view-angle change command; and second control means for controlling the adjustment of the view angle so as to be substantially transferred from the second adjustment means to the first adjustment means, while maintaining the view angle commanded by the commanding means.
According to another aspect of the present invention, the foregoing object has been achieved through the provision of an image pickup apparatus including: first adjustment means for optically adjusting a view angle; second adjustment means for electronically adjusting the view angle; commanding means for giving a view-angle change command; first control means for simultaneously driving the first adjustment means and the second adjustment means in order to change the view angle to a view angle based on the view-angle change command provided by the commanding means; and second control means for controlling the adjustment of the view angle so as to be substantially transferred from the second adjustment means to the first adjustment means, while maintaining the view angle corresponding to the view-angle change command.
According to still another aspect of the present invention, the foregoing object has been achieved through the provision of an image pickup apparatus including: a zoom lens for optically adjusting a view angle; an image pickup device for capturing the image of a subject through the zoom lens; an electronic zoom processing circuit for the electronic zoom processing of an output signal obtained from the image pickup device; a zoom switch for giving a view-angle change command; a first control circuit for causing said electronic zoom processing circuit to adjust the view angle based on the view-angle change command; and a second control circuit for controlling the adjustment of the view angle so as to be substantially transferred from the electronic zoom processing circuit to the zoom lens, while maintaining the view angle corresponding to the view angle change command.
According to a further aspect of the present invention, the foregoing object has been achieved through the provision of an image pickup apparatus including: a zoom lens for optically adjusting a view angle; an image pickup device for capturing the image of a subject through the zoom lens; an electronic zoom processing circuit for the electronic zoom processing of an output signal obtained from the image pickup device; a zoom switch for giving a view-angle change command; a first control circuit for causing the zoom lens and the electronic zoom processing circuit to adjust the view angle based on the view-angle change command; and a second control circuit for controlling the adjustment of the view angle so as to be substantially transferred from the electronic zoom processing circuit to the zoom lens, while maintaining the view angle corresponding to the view-angle change command.
According to a still further aspect of the present invention, the foregoing object has been achieved through the provision of an image pickup apparatus including: a zoom lens for optically adjusting a view angle; an image pickup device for capturing the image of a subject through the zoom lens; an electronic zoom processing circuit for the electronic zoom processing of an output signal from the image pickup device; an auto-zoom switch for setting the size of the subject within a screen to a predetermined size; a memory in which the magnification of the image of the subject and the distance to the subject, which have been set by the auto-zoom switch, are stored; an operation processing circuit for calculating a view angle to maintain the size of the subject image (based on a change between the distance to the subject and the present distance to the subject) and the magnification of the subject image, which are stored in the memory; a first control circuit for driving the electronic zoom processing circuit to obtain the view angle calculated by the operation processing circuit; and a second control circuit for controlling the adjustment of the view angle so as to be substantially transferred from the electronic zoom processing circuit to the zoom lens, while maintaining the view angle calculated by the operation processing circuit.
According to another aspect of the present invention, the foregoing object has been achieved through the provision of an image pickup apparatus including: a zoom lens for optically adjusting a view angle; an image pickup device for capturing the image of a subject through the zoom lens; an electronic zoom processing circuit for the electronic zoom processing of an output signal from the image pickup device; an auto-zoom switch for setting the size of the subject within a screen to a predetermined size; a memory in which the magnification of the image of the subject and the distance to the subject (which have been set by the auto-zoom switch) are stored; an operation processing circuit for calculating a view angle to maintain the size of the subject image (based on a change between the distance to the subject and the present distance to the subject) and the magnification of the subject image, which are stored in the memory; a first control circuit for simultaneously driving the zoom lens and the electronic zoom processing circuit to obtain the view angle calculated by the operation processing circuit; and a second control circuit for controlling the adjustment of the view angle so as to be substantially transferred from the electronic zoom processing circuit to the zoom lens, while maintaining the view angle obtained by the first control circuit.
According to an additional aspect of the present invention, the foregoing object has been achieved through the provision of a storage medium in which a program for adjusting a view angle for an image pickup apparatus is stored, the storage medium activating the processes of: executing electronic zooming in order to obtain a view angle based on a view-angle change command; and maintaining the view angle obtained by the electronic zooming by substantially driving a zoom lens, with the view angle unchanged.
According to a further aspect of the present invention, the foregoing object has been achieved through the provision of a storage medium in which a program for adjusting a view angle for an image pickup apparatus is stored, the storage medium activating the processes of: executing electronic zooming and the driving of a zoom lens in order to obtain a view angle based on a view-angle change command; and maintaining the view angle obtained by the electronic zooming by substantially driving the zoom lens, with the view angle unchanged.
Other objects and features of the present invention will become apparent from the following description and the attached drawings.